Though the market for synthetic membranes is growing toward 2.7 billion dollars in the next decade, there is an absence of technology for in situ characterization of the pore structure of thin film membranes. This is slowing progress in membrane development, limiting understanding of membrane function, and causing higher costs to develop and manufacture membranes. TPL proposes a sensor system able to make measurements on thin films that have exactly the same characteristics as finished membranes. The sensor will be based on a miniature, solid state, SAW device with mass sensitivity of 10-12g. During Phase I, mesoporous, microporous, nonporous and closed porous thin films will be evaluated. At constant temperature, the response of the sensor to absorption of gas by the thin film, and the pressure of a gas as it interacts with the film will permit detailed assessment of membrane function not possible with current techniques. TPL and its collaborators have substantial experience in the development of sensors and instrumentation systems, and in measuring porosity characteristics of both thin films and powders. The vast improvement in analytical capability achieved with the new system will result in new, less expensive membranes for many applications in the fields of biotechnology and medicine. PROPOSED COMMERCIAL APPLICATION Membrane development and manufacture, hermetic seals, medical and biotechnology products.